EP4290324B1

EP4290324B1 - Automatic skid offline-cleaning guidance and control system and method

Info

Publication number: EP4290324B1
Application number: EP23159708.9A
Authority: EP
Inventors: Yongsheng CHANG; Sheng FENG; Zhifei Ma; Lei Yao; Jinsong Zhang; Xiaogang Peng; Song Li
Original assignee: Chongqing Changan Automobile Co Ltd
Current assignee: Chongqing Changan Automobile Co Ltd
Priority date: 2022-06-06
Filing date: 2023-03-02
Publication date: 2025-05-21
Anticipated expiration: 2043-03-02
Also published as: CN115047820B; EP4290324A1; CN115047820A; EP4290324C0; MX2023003769A

Description

Field of the Invention

The present disclosure belongs to the technical field of automobile production, and in particular, relates to an automatic skid offline-cleaning guidance and control system and method.

Background of the Invention

In a painting workshop in the automobile industry, in order to prolong the service life of skids and to ensure that the production line is not shut down due to paint accumulation and adhesion, skids with serious paint accumulation and adhesion need to be cleaned offline. At present, manual inspection is mainly used to determine whether a skid needs to be taken offline, and the skid will be taken offline manually. However, long-term in the painting and spraying sites is detrimental to the health of people, resulting in high labor costs, and any omissions in the inspection may lead to incomplete cleaning and eventually cause losses by shutdown of the production line.
Therefore, there is a need to develop an automatic skid offline-cleaning guidance and control system and method.

Summary of the Invention

It is an object of the present application to provide an automatic skid offline-cleaning guidance and control system and method for automatically monitoring paint fouling on skids and automatically guiding and controlling a skid that has reached the criterion for cleaning to be taken offline.
According to the present disclosure, an automatic skid offline-cleaning guidance and control system includes a PLC control module, a skid position tracking and paint fouling condition monitoring subsystem, a skid offline control subsystem, a skid detection subsystem, and a human-computer interaction interface, the PLC control module being connected to the skid position tracking and paint fouling condition monitoring subsystem, the skid offline control subsystem, the skid detection subsystem, and the human-computer interaction interface; wherein

the PLC control module is configured to read a serial number of a skid and identify a position of the skid;
the skid position tracking and paint fouling condition monitoring subsystem is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module, detect a paint fouling condition of the skid, and send a skid cleaning request to the PLC control module when determining that the skid needs to be cleaned;
the PLC control module sends a skid cleaning instruction to the skid offline control subsystem based on the skid cleaning request, and the skid offline control subsystem performs an offline operation based on the skid cleaning instruction;
the human-computer interaction interface is configured to display hardware status of the whole guidance and control system, information about the paint fouling condition of the skid, and information about the position of the skid.

Optionally, the skid position tracking and paint fouling condition monitoring subsystem includes a skid paint fouling detection and position monitoring module, a skid information data storage module, and a communication module, the skid paint fouling detection and position monitoring module being connected to the skid information data storage module and the communication module; wherein

the skid paint fouling detection and position monitoring module is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module to monitor a paint fouling condition of the skid and detect paint fouling on the skid, and send a skid cleaning request instruction to the PLC control module;
the skid information data storage module is configured to record the information about the position of the skid and a state of the skid, the state of the skid including an offline state and an online state;
the communication module is configured to communicate the information about the position of the skid, information about the state of the skid, and a cleaning request label.

Optionally, the skid offline control subsystem includes an input/output module, a first enabling control module, a first action control module, a skid offline control frequency converter, a skid offline control motor, a second enabling control module, a second action control module, a skid rotation control frequency converter, and a skid rotation control motor; the skid rotation control frequency converter being connected to the skid rotation control motor, the second enabling control module and the second action control module; the skid offline control frequency converter being connected to the skid offline control motor, the first enabling control module and the first action control module; the first enabling control module, the first action control module, the second enabling control module and the second action control module being connected to the input/output module, and the input/output module being connected to the PLC control module; wherein

the skid rotation control frequency converter is configured to control the skid rotation control motor to perform a rotation action upon reception of a rotation control instruction sent by the PLC control module through the second enabling control module and the second action control module;
the skid offline control frequency converter is configured to control the skid offline control motor to perform an offline action upon reception of an offline control instruction sent by the PLC control module through the first enabling control module and the first action control module;
the input-output module is configured for in-cabinet IO signal communication.

Optionally, the skid detection subsystem includes a skid path selection in-place detection switch, a skid offline in-place detection switch, a skid passing-point count detection module, an offline in-place skid information detection module, a skid information writing module, a skid rotation in-place detection switch, and a remote input/output module; the remote input/output module being connected to the skid path selection in-place detection switch, the skid offline in-place detection switch, the skid passing-point count detection module, the offline in-place skid information detection module, the skid information writing module, the skid rotation in-place detection switch and the PLC control module; wherein

the offline in-position skid information detection module is configured to detect the position of the skid, and acquire the serial number of the skid and information about the cleaning request;
the skid path selection in-position detection switch, the skid rotation in-position detection switch and the skid offline in-position detection switch are configured to detect the position of the skid;
the skid passing-point count detection module is configured to detect the position of the skid and write a cleaning request flag;
the skid information writing module is configured to change the cleaning request flag;
the remote input/output module is configured for distributed IO signal communication.

Optionally, the communication module is an Ethernet communication module.
Optionally, each of the first enabling control module, the first action control module, the second enabling control module and the second action control module is a relay.
Optionally, each of the skid passing-point count detection module, the offline in-position skid information detection module and the skid information writing module is an RFID module.
In a second aspect of the present disclosure, an automatic skid offline-cleaning guidance and control method, using the automatic skid offline-cleaning guidance and control system according to the present disclosure, includes the following steps of:

S1: paint fouling condition monitoring:
when a skid detection subsystem senses a skid passing by, a skid position tracking and paint fouling condition monitoring subsystem reads a serial number of the skid through a PLC control module; the skid position tracking and paint fouling condition monitoring subsystem acquires the serial number of the skid and information about a position of the skid from the PLC control module, detects a paint fouling condition of the skid, and sends a skid cleaning request to the PLC control module when determining that the skid needs to be cleaned; and
S2: skid offline control:
the PLC control module sends a skid cleaning instruction to the skid offline control subsystem based on the skid cleaning request, and the skid offline control subsystem performs an offline operation based on the skid cleaning instruction.

Optionally, the step S1 specifically includes:

S11: when a skid passing-point count detection module senses a skid passing by, a skid paint fouling detection and position monitoring module reads a serial number of the skid through the PLC control module;
S12: the skid paint fouling detection and position monitoring module determines whether the skid passing by a position of the skid passing-point count detection module is labeled as offline or not; if the skid is labeled as offline, the skid paint fouling detection and position monitoring module clears a passing-point count recorded in real time by a skid information data storage module to zero, and labels the skid as online; and if the skid is not labeled as offline;
S13: the skid paint fouling detection and position monitoring module calculates the passing-point account of each skid, and stores the passing-point account of each skid in the skid information data storage module; and
S14: the skid paint fouling detection and position monitoring module determines whether the passing-point count of the skid exceeds a preset threshold or not; if the passing-point count of the skid exceeds the preset threshold, the skid paint fouling detection and position monitoring module labels the serial number of the skid, whose passing-point count exceeds the preset threshold, with a cleaning request through the PLC control module and the skid passing-point count detection module, and a current paint fouling condition monitoring program is ended; and if the passing-point count of the skid does not exceed the preset threshold, the current paint fouling condition monitoring program is directly ended.

Optionally, the step S2 specifically includes:

S21: when the offline in-position skid information detection module senses a skid passing by, the PLC control module reads the serial number of the skid;
S22: the offline in-position skid information detection module detects whether the currently passed skid is labeled with a cleaning request or not; if the currently passed skid is labeled with a cleaning request, go to the next step; if the currently passed skid is not labeled with a cleaning request, the current skid offline control program is ended;
S23: the PLC control module outputs a rotation action signal for a skid rotation control motor in response to detection of a skid by a skid path selection in-position detection switch;
S24: the PLC control module outputs a stop signal for the skid rotation control motor and a start signal for a skid offline control motor in response to detection of a skid by a skid rotation in-position detection switch;
S25: the PLC control module outputs a stop signal for the skid offline control motor in response to detection of a skid by a skid offline in-position detection switch;
S26: the PLC control module changes a cleaning request flag through a skid information writing module; and
S27: the skid paint fouling detection and position monitoring module labels a state of the skid recorded in real time by the skid information data storage module as offline.

The present disclosure has the following advantages. The disclosed system and method is capable of automatically monitoring paint fouling on skids, and automatically guiding and controlling a skid that has reached the criterion for cleaning to be taken offline. Besides, the costs reduced, and manual inspection can be eliminated.

Brief Description of the Drawings

Fig. 1 is a schematic block diagram of an automatic skid offline-cleaning guidance and control system in accordance with an embodiment of the present disclosure;
Fig. 2 is a flowchart illustrating paint fouling condition monitoring and control of the automatic skid offline-cleaning guidance and control system in accordance with an embodiment of the present disclosure; and
Fig. 3 is a flowchart illustrating skid offline control of the automatic skid offline-cleaning guidance and control system in accordance with an embodiment of the present disclosure.

In the figures: 1) skid offline control subsystem; 2) skid position tracking and paint fouling condition monitoring subsystem; 3) a PLC control module; 4) human-computer interaction interface; and 5) skid detection subsystem.

Detailed Description of the Embodiments

Hereinafter, the present disclosure will be described in detail with reference to the accompanying drawings.
In this embodiment, as shown in Fig. 1, an automatic skid offline-cleaning guidance and control system includes a PLC control module 3, a skid position tracking and paint fouling condition monitoring subsystem 2, a skid offline control subsystem 1, a skid detection subsystem 5, and a human-computer interaction interface 4, the PLC control module 3 being connected to the skid position tracking and paint fouling condition monitoring subsystem 2, the skid offline control subsystem 1, the skid detection subsystem 5, and the human-computer interaction interface 4. The PLC control module 3 is configured to read a serial number of a skid and identify a position of the skid. The skid position tracking and paint fouling condition monitoring subsystem 2 is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module 3, detect a paint fouling condition of the skid, and send a skid cleaning request to the PLC control module 3 when determining that the skid needs to be cleaned. The PLC control module 3 sends a skid cleaning instruction to the skid offline control subsystem 1 based on the skid cleaning request, and the skid offline control subsystem 1 performs an offline operation on the skid based on the skid cleaning instruction. The human-computer interaction interface 4 is configured to display hardware status of the whole guidance and control system, information about the paint fouling condition of the skid, and information about the position of the skid.
As shown in Fig. 1, in this embodiment, the skid position tracking and paint fouling condition monitoring subsystem 2 includes a skid paint fouling detection and position monitoring module, a skid information data storage module, and a communication module, the skid paint fouling detection and position monitoring module being connected to the skid information data storage module and the communication module. The skid paint fouling detection and position monitoring module is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module 3 to monitor a paint fouling condition of the skid and detect paint fouling on the skid, and send a skid cleaning request instruction to the PLC control module 3. The skid information data storage module is configured to record the information about the position of the skid and a state of the skid, the state of the skid including an offline state and an online state; The communication module is configured to communicate the information about the position of the skid, information about the state of the skid, and a cleaning request label.
As shown in Fig. 1, in this embodiment, the skid offline control subsystem 1 includes an input/output module, a first enabling control module, a first action control module, a skid offline control frequency converter, a skid offline control motor, a second enabling control module, a second action control module, a skid rotation control frequency converter, and a skid rotation control motor; the skid rotation control frequency converter being connected to the skid rotation control motor, the second enabling control module and the second action control module; the skid offline control frequency converter being connected to the skid offline control motor, the first enabling control module and the first action control module; the first enabling control module, the first action control module, the second enabling control module and the second action control module being connected to the input/output module, and the input/output module being connected to the PLC control module 3. The skid rotation control frequency converter is configured to control the skid rotation control motor to perform a rotation action upon reception of a rotation control instruction sent by the PLC control module 3 through the second enabling control module and the second action control module. The skid offline control frequency converter is configured to control the skid offline control motor to perform an offline action upon reception of an offline control instruction sent by the PLC control module 3 through the first enabling control module and the first action control module. The input-output module is configured for in-cabinet IO signal communication.
As shown in Fig. 1, in this embodiment, the skid detection subsystem includes a skid path selection in-position detection switch, a skid offline in-position detection switch, a skid passing-point count detection module, an offline in-position skid information detection module, a skid information writing module, a skid rotation in-position detection switch, and a remote input/output module; the remote input/output module being connected to the skid path selection in-position detection switch, the skid offline in-position detection switch, the skid passing-point count detection module, the offline in-position skid information detection module, the skid information writing module, the skid rotation in-position detection switch and the PLC control module 3. The offline in-position skid information detection module is configured to detect the position of the skid, and acquire the serial number of the skid and information about the cleaning request. The skid path selection in-position detection switch, the skid rotation in-position detection switch and the skid offline in-position detection switch are configured to detect the position of the skid. The skid passing-point count detection module is configured to detect the position of the skid and write a cleaning request flag. The skid information writing module is configured to change the cleaning request flag. The remote input/output module is configured for distributed IO signal communication.
The system is capable of automatically monitoring paint fouling on skids, and automatically guiding and controlling a skid that has reached the criterion for cleaning to be taken offline.
In this embodiment, the communication module is an Ethernet communication module.
In this embodiment, each of the first enabling control module, the first action control module, the second enabling control module and the second action control module is a relay.
In this embodiment, each of the skid passing-point count detection module, the offline in-position skid information detection module and the skid information writing module is an RFID module.
In this embodiment, an automatic skid offline-cleaning guidance and control method, using the automatic skid offline-cleaning guidance and control system according to the embodiments of the present disclosure, includes the following steps of:

S1: paint fouling condition monitoring:
when a skid detection subsystem 5 senses a skid passing by, a skid position tracking and paint fouling condition monitoring subsystem 2 reads a serial number of the skid through a PLC control module 3; the skid position tracking and paint fouling condition monitoring subsystem 2 acquires the serial number of the skid and information about a position of the skid from the PLC control module 3, detects a paint fouling condition of the skid, and sends a skid cleaning request to the PLC control module 3 when determining that the skid needs to be cleaned; and
S2: skid offline control:
the PLC control module 3 sends a skid cleaning instruction to the skid offline control subsystem 1 based on the skid cleaning request, and the skid offline control subsystem 1 performs an offline operation on the skid based on the skid cleaning instruction.

As shown in Fig. 2, in this embodiment, the step S1 specifically includes:

S11: when a skid passing-point count detection module senses a skid passing by, a skid paint fouling detection and position monitoring module reads a serial number of the skid through the PLC control module 3;
S12: the skid paint fouling detection and position monitoring module determines whether the skid passing by a position of the skid passing-point count detection module is labeled as offline or not; if the skid is labeled as offline, the skid paint fouling detection and position monitoring module clears a passing-point count recorded in real time by a skid information data storage module to zero, and labels the skid as online; and if the skid is not labeled as offline;
S13: the skid paint fouling detection and position monitoring module calculates the passing-point account of each skid, and stores the passing-point account of each skid in the skid information data storage module; and
S14: the skid paint fouling detection and position monitoring module determines whether the passing-point count of the skid exceeds a preset threshold or not; if the passing-point count of the skid exceeds the preset threshold, the skid paint fouling detection and position monitoring module labels the serial number of the skid, whose passing-point count exceeds the preset threshold, with a cleaning request (i.e., set a flat bit of the cleaning request to be 1) through the PLC control module 3 and the skid passing-point count detection module, and a current paint fouling condition monitoring program is ended; and if the passing-point count of the skid does not exceed the preset threshold, the current paint fouling condition monitoring program is directly ended.

As shown in Fig. 3, in this embodiment, the step S2 specifically includes:

S21: when the offline in-position skid information detection module senses a skid passing by, the PLC control module 3 reads the serial number of the skid;
S22: the offline in-position skid information detection module detects whether the currently passed skid is labeled with a cleaning request or not; if the currently passed skid is labeled with a cleaning request (i.e., the flag bit is 1), go to the next step; if the currently passed skid is not labeled with a cleaning request (i.e., the flag bit is 0), the current skid offline control program is ended;
S23: the PLC control module 3 outputs a rotation action signal for a skid rotation control motor in response to detection of a skid by a skid path selection in-position detection switch;
S24: the PLC control module 3 outputs a stop signal for the skid rotation control motor and a start signal for a skid offline control motor in response to detection of a skid by a skid rotation in-position detection switch;
S25: the PLC control module 3 outputs a stop signal for the skid offline control motor in response to detection of a skid by a skid offline in-position detection switch;
S26: the PLC control module 3 changes a cleaning request flag (i.e., set the flag bit to be 0) through a skid information writing module; and
S27: the skid paint fouling detection and position monitoring module labels a state of the skid recorded in real time by the skid information data storage module as offline.

The method is capable of automatically monitoring paint fouling on skids, and automatically guiding and controlling a skid that has reached the criterion for cleaning to be taken offline.
The embodiments described above are preferred embodiments of the present disclosure, but the embodiments of the present disclosure are not limited to the embodiments described above, and any other changes, modifications, substitutions, combinations and simplifications made without departing from the principles of the present disclosure are to be construed as equivalent substitutions within the scope of the present disclosure.

Claims

An automatic skid offline-cleaning guidance and control system, comprising: a PLC control module (3), a skid position tracking and paint fouling condition monitoring subsystem (2), a skid offline control subsystem (1), a skid detection subsystem (5), and a human-computer interaction interface (4), the PLC control module (3) being connected to the skid position tracking and paint fouling condition monitoring subsystem (2), the skid offline control subsystem (1), the skid detection subsystem (5), and the human-computer interaction interface (4); characterized in that
the PLC control module (3) is configured to read a serial number of a skid and identify a position of the skid;

the skid position tracking and paint fouling condition monitoring subsystem (2) is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module (3), detect a paint fouling condition of the skid, and send a skid cleaning request to the PLC control module (3) when determining that the skid needs to be cleaned;

the PLC control module (3) sends a skid cleaning instruction to the skid offline control subsystem (1) based on the skid cleaning request, and the skid offline control subsystem (1) performs an offline operation on the skid based on the skid cleaning instruction;

the human-computer interaction interface (4) is configured to display hardware status of the whole guidance and control system, information about the paint fouling condition of the skid, and information about the position of the skid.
The automatic skid offline-cleaning guidance and control system according to claim 1, wherein the skid position tracking and paint fouling condition monitoring subsystem (2) comprises a skid paint fouling detection and position monitoring module, a skid information data storage module, and a communication module, the skid paint fouling detection and position monitoring module being connected to the skid information data storage module and the communication module; wherein
the skid paint fouling detection and position monitoring module is configured to acquire the serial number of the skid and information about the position of the skid from the PLC control module (3) to monitor a paint fouling condition of the skid and detect paint fouling on the skid, and send a skid cleaning request instruction to the PLC control module (3);

the skid information data storage module is configured to record the information about the position of the skid and a state of the skid, the state of the skid including an offline state and an online state;

the communication module is configured to communicate the information about the position of the skid, information about the state of the skid, and a cleaning request label.
The automatic skid offline-cleaning guidance and control system according to claim 2, wherein the skid offline control subsystem (1) comprises an input/output module, a first enabling control module, a first action control module, a skid offline control frequency converter, a skid offline control motor, a second enabling control module, a second action control module, a skid rotation control frequency converter, and a skid rotation control motor; the skid rotation control frequency converter being connected to the skid rotation control motor, the second enabling control module and the second action control module; the skid offline control frequency converter being connected to the skid offline control motor, the first enabling control module and the first action control module; the first enabling control module, the first action control module, the second enabling control module and the second action control module being connected to the input/output module, and the input/output module being connected to the PLC control module (3); wherein
the skid rotation control frequency converter is configured to control the skid rotation control motor to perform a rotation action upon reception of a rotation control instruction sent by the PLC control module (3) through the second enabling control module and the second action control module;

the skid offline control frequency converter is configured to control the skid offline control motor to perform an offline action upon reception of an offline control instruction sent by the PLC control module (3) through the first enabling control module and the first action control module;

the input-output module is configured for in-cabinet IO signal communication.
The automatic skid offline-cleaning guidance and control system according to claim 3, wherein the skid detection subsystem comprises a skid path selection in-position detection switch, a skid offline in-position detection switch, a skid passing-point count detection module, an offline in-position skid information detection module, a skid information writing module, a skid rotation in-position detection switch, and a remote input/output module; the remote input/output module being connected to the skid path selection in-position detection switch, the skid offline in-position detection switch, the skid passing-point count detection module, the offline in-position skid information detection module, the skid information writing module, the skid rotation in-position detection switch and the PLC control module (3); wherein
the offline in-position skid information detection module is configured to detect the position of the skid, and acquire the serial number of the skid and information about the cleaning request;

the skid path selection in-position detection switch, the skid rotation in-position detection switch and the skid offline in-position detection switch are configured to detect the position of the skid;

the skid passing-point count detection module is configured to detect the position of the skid and write a cleaning request flag;

the skid information writing module is configured to change the cleaning request flag;

the remote input/output module is configured for distributed IO signal communication.
The automatic skid offline-cleaning guidance and control system according to any one of claims 2 to 4, wherein the communication module is an Ethernet communication module.
The automatic skid offline-cleaning guidance and control system according to claim 3 or 4, wherein each of the first enabling control module, the first action control module, the second enabling control module and the second action control module is a relay.
The automatic skid offline-cleaning guidance and control system according to claim 4, wherein each of the skid passing-point count detection module, the offline in-position skid information detection module and the skid information writing module is an RFID module.
An automatic skid offline-cleaning guidance and control method characterized by using the automatic skid offline-cleaning guidance and control system as claimed in any one of claims 4 to 7, the method comprising the steps of:
S1: paint fouling condition monitoring:
when a skid detection subsystem (5) senses a skid passing by, a skid position tracking and paint fouling condition monitoring subsystem (2) reads a serial number of the skid through a PLC control module (3); the skid position tracking and paint fouling condition monitoring subsystem (2) acquires the serial number of the skid and information about a position of the skid from the PLC control module (3), detects a paint fouling condition of the skid, and sends a skid cleaning request to the PLC control module (3) when determining that the skid needs to be cleaned; and

S2: skid offline control:
the PLC control module (3) sends a skid cleaning instruction to a skid offline control subsystem (1) based on the skid cleaning request, and the skid offline control subsystem (1) performs an offline operation on the skid based on the skid cleaning instruction.
The automatic skid offline-cleaning guidance and control method according to claim 8, wherein the step S1 specifically comprises:
S11: when a skid passing-point count detection module senses a skid passing by, a skid paint fouling detection and position monitoring module reads a serial number of the skid through the PLC control module (3);

S12: the skid paint fouling detection and position monitoring module determines whether the skid passing by a position of the skid passing-point count detection module is labeled as offline or not; if the skid is labeled as offline, the skid paint fouling detection and position monitoring module clears a passing-point count recorded in real time by a skid information data storage module to zero, and labels the skid as online; and if the skid is not labeled as offline;

S13: the skid paint fouling detection and position monitoring module calculates the passing-point account of each skid, and stores the passing-point account of each skid in the skid information data storage module; and

S14: the skid paint fouling detection and position monitoring module determines whether the passing-point count of the skid exceeds a preset threshold or not; if the passing-point count of the skid exceeds the preset threshold, the skid paint fouling detection and position monitoring module labels the serial number of the skid, whose passing-point count exceeds the preset threshold, with a cleaning request through the PLC control module (3) and the skid passing-point count detection module, and a current paint fouling condition monitoring program is ended; and if the passing-point count of the skid does not exceed the preset threshold, the current paint fouling condition monitoring program is directly ended.
The automatic skid offline-cleaning guidance and control method according to claim 9, wherein the step S2 specifically comprises:
S21: when the offline in-position skid information detection module senses a skid passing by, the PLC control module (3) reads the serial number of the skid;

S22: the offline in-position skid information detection module detects whether the currently passed skid is labeled with a cleaning request or not; if the currently passed skid is labeled with a cleaning request, go to the next step; if the currently passed skid is not labeled with a cleaning request, the current skid offline control program is ended;

S23: the PLC control module (3) outputs a rotation action signal for a skid rotation control motor in response to detection of a skid by a skid path selection in-position detection switch;

S24: the PLC control module (3) outputs a stop signal for the skid rotation control motor and a start signal for a skid offline control motor in response to detection of a skid by a skid rotation in-position detection switch;

S25: the PLC control module (3) outputs a stop signal for the skid offline control motor in response to detection of a skid by a skid offline in-position detection switch;

S26: the PLC control module (3) changes a cleaning request flag through a skid information writing module; and

S27: the skid paint fouling detection and position monitoring module labels a state of the skid recorded in real time by the skid information data storage module as offline.